JavaBean
package com.itheima.domain;
import java.math.BigDecimal;
public class BigDecimalDemo {
private double firstNum;
private char fuHao='+';
private double secondNum;
public double getFirstNum() {
return firstNum;
}
public void setFirstNum(double firstNum) {
this.firstNum = firstNum;
}
public char getFuHao() {
return fuHao;
}
public void setFuHao(char fuHao) {
this.fuHao = fuHao;
}
public double getSecondNum() {
return secondNum;
}
public void setSecondNum(double secondNum) {
this.secondNum = secondNum;
}
public double toResult(){
double result = 0;
switch (fuHao) {
case '+':
result=new BigDecimal(firstNum).add(new BigDecimal(secondNum)).doubleValue();
break;
case '-':
result=new BigDecimal(firstNum).subtract(new BigDecimal(secondNum)).doubleValue();
break;
case '*':
result=new BigDecimal(firstNum).multiply(new BigDecimal(secondNum)).doubleValue();
break;
case '/':
if(secondNum!=0){
result=new BigDecimal(firstNum).divide(new BigDecimal(secondNum)).doubleValue();
}else{
throw new RuntimeException();
}
break;
default:
break;
}
return result;
}
}
jsp页面
<%@page import="javax.servlet.jsp.tagext.TryCatchFinally"%>
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Insert title here</title>
</head>
<body>
<jsp:useBean id="bd" class="com.itheima.domain.BigDecimalDemo"></jsp:useBean>
<jsp:setProperty property="*" name="bd"/>
<%
double a;
try{
a=bd.toResult();
}catch(Exception e){
out.println("除法第二个数不能为0");
a=0;//如果出现异常，则打印出0
}
%>
<hr/>
您的计算结果是：<jsp:getProperty property="firstNum" name="bd"/>
<jsp:getProperty property="fuHao" name="bd"/>
<jsp:getProperty property="secondNum" name="bd"/>
=<%=a %>
<hr/>
<form action="" method="get">
<table border='1' width='50%'>
<tr>
<td>您输入的第一个数</td>
<td><input type="text" name="firstNum"></td>
</tr>
<tr>
<td>您选择的运算符</td>
<td>
<select name="fuHao">
<option value="+">+</option>
<option value="-">-</option>
<option value="*">*</option>
<option value="/">/</option>
</select>
</td>
</tr>
<tr>
<td>你输入的第二个数是</td>
<td><input type="text" name="secondNum"></td>
</tr>
<tr>
<td colspan="2"><input type="submit" value="计算"></td>
</tr>
</table>
</form>
</body>
</html>